Area units are lengths, squared
A square meter is the area of a square with 1 m sides. Convert each side to feet and you get a square 3.2808… ft by 3.2808… ft, which is 10.7639… square feet. Every area factor works this way: take the length factor and square it. Since a foot is exactly 0.3048 m, a square foot is exactly 0.3048 × 0.3048 = 0.09290304 m², and the same logic gives exact values for square inches, square yards and square miles.
Two units in the converter are not squares of a length unit:
- The hectare is 10,000 m², a square 100 m on each side. It is the standard land unit in most countries, and 100 hectares make a square kilometer.
- The acre is 4,840 square yards, or 43,560 square feet. It is used for land in the United States, the United Kingdom, Canada, Australia and other countries with an English-measure history. An acre has no fixed shape; the classic picture is a strip one furlong (660 ft) by one chain (66 ft).
The converter changes your value into square meters and then into the target unit, showing the combined factor in the working line.
Area formulas
All four factors are exact consequences of the 1959 yard of 0.9144 m. A square mile is exactly 640 acres.
| Unit | Square meters | Typical use |
|---|---|---|
| Square centimeter (cm²) | 0.0001 | Paper, screens, small parts |
| Square inch (in²) | 0.00064516 | US and UK small areas |
| Square foot (ft²) | 0.09290304 | Floor area in the US and UK property listings |
| Square yard (yd²) | 0.83612736 | Carpet and turf in the US |
| Square meter (m²) | 1 | Floor area in most of the world |
| Acre | 4,046.8564224 | Land in the US, UK and elsewhere |
| Hectare (ha) | 10,000 | Land and farms worldwide |
| Square kilometer (km²) | 1,000,000 | Cities, regions, countries |
| Square mile (mi²) | 2,589,988.110336 | Regions in the US and UK |
International acre or US survey acre
Before 2023, US land measurements could use the US survey foot (1200/3937 m) instead of the international foot (0.3048 m). An acre of 43,560 survey feet² comes to about 4,046.8726 m², roughly 0.016 m² or 4 parts per million more than the international acre of 4,046.8564224 m². NIST and NOAA deprecated the survey foot after December 31, 2022, and the acre is now expressed in international feet. The converter uses the international acre. Old deeds and plats may still be written in survey units, but the difference only matters for very large tracts or precise surveying.
Worked examples
- Area in square meters: 4 × 3.5 = 14 m².
- Divide by the size of a square foot: 14 ÷ 0.09290304 = 150.695 ft².
- Multiply by the exact factor: 2,000 × 0.09290304 = 185.80608 m².
- Round to the nearest square meter for a listing: 186 m².
- One acre is 0.40468564224 ha.
- 5 × 0.40468564224 = 2.0234 ha, a little over two hectares.
- A mile is 1.609344 km, so a square mile is 1.609344² = 2.58999 km².
- In acres: 2,589,988.110336 m² ÷ 4,046.8564224 m² = 640 exactly.
Area tables
| Square meters (m²) | Square feet (ft²) | Square yards (yd²) |
|---|---|---|
| 1 | 10.7639 | 1.19599 |
| 5 | 53.8196 | 5.97995 |
| 10 | 107.639 | 11.9599 |
| 15 | 161.459 | 17.9399 |
| 20 | 215.278 | 23.9198 |
| 25 | 269.098 | 29.8998 |
| 50 | 538.196 | 59.7995 |
| 75 | 807.293 | 89.6993 |
| 100 | 1,076.39 | 119.599 |
| 150 | 1,614.59 | 179.399 |
| 200 | 2,152.78 | 239.198 |
| Hectares (ha) | Acres (ac) | Square kilometers (km²) |
|---|---|---|
| 0.5 | 1.23553 | 0.005 |
| 1 | 2.47105 | 0.01 |
| 2 | 4.94211 | 0.02 |
| 5 | 12.3553 | 0.05 |
| 10 | 24.7105 | 0.1 |
| 50 | 123.553 | 0.5 |
| 100 | 247.105 | 1 |
| 1,000 | 2,471.05 | 10 |
Pitfalls with square units
- Using the length factor for an area. 10 m² × 3.28 = 32.8 is wrong; the right answer is 107.6 ft². If a result looks about a third of what you expected, the factor was not squared.
- Rounding the sides before multiplying. Measure 3.5 m as “11 ft” and 4 m as “13 ft” and the room becomes 143 ft² instead of 150.7 ft². Convert the area once, from exact measurements.
- Reading “m2” as “2 m”. Square meters (m²) are a unit; two meters is a length. When typing, “sq m” or “m^2” avoids the confusion.
- Mixing hectares and acres in price comparisons. A price per hectare is about 2.47 times a price per acre for the same land value.
Property listings sometimes quote gross area including walls, and sometimes net floor area. The converter converts whatever figure you give it; it cannot tell you which one a listing used.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, Appendix B, National Institute of Standards and Technology.
- U.S. Survey Foot, National Institute of Standards and Technology.
- Deprecation of the United States (U.S.) Survey Foot (Federal Register notice, October 5, 2020), Federal Register (NIST and NOAA).